A former nurse accused of murdering eight elderly patients allegedly used lethal doses of insulin to kill those who angered her, CTV News has learned.

Family members of several victims said police investigators informed them that the killings were done to patients who “pissed (Elizabeth) Wettlaufer off.” Some family members have described their loved ones falling into a sudden coma before dying.

Insulin overdoses can drastically lower a person’s blood sugar level and lead to a coma and, in the most extreme cases, death.

Elizabeth Wettlaufer, of Woodstock, Ont., allegedly confessed to the killings while undergoing treatment for a narcotics addiction at a Toronto psychiatric hospital.

Officials from Toronto’s Centre for Addiction and Mental Health notified Toronto Police after Wettlaufer, 49, told someone at the facility about her involvement in the deaths, sources told CTV News.

Wettlaufer was undergoing addiction treatment for narcotics at CAMH up until a few weeks ago, sources said. Court documents reveal she was also seeking mental health treatment in Woodstock.

Wettlaufer was charged Tuesday with eight counts of first-degree murder in the deaths of residents at two nursing homes in Woodstock and London, Ont.

If she is found guilty, Wettlaufer would be considered a serial killer.

Police allege that Wettlaufer administered a lethal dose of a drug to the victims, who range in age from 75 to 96. Police have not identified the suspected drug or discussed an alleged motive.

Wettlaufer recently signed a peace bond that laid out strict conditions prior to her arrest. She was banned from possessing insulin, alcohol or any other drug, had a curfew of 7 p.m. and was only allowed to leave her home or her parents’ home to attend Alcoholics Anonymous meetings.

CTV News spoke with Wettlaufer's father, who declined to appear on camera but said his daughter is a kind, considerate woman who comes from a faith-driven family.

Neighbours said Wettlaufer spoke openly about her struggle with addiction.

“Recently, three weeks ago, she was in for 15 or 16 days,” said one neighbour, who asked to not be identified.

A friend of the suspect, Nancy Gilbert, told The Canadian Press that Wettlaufer appeared to be in good spirits after finishing her second stint in rehab at CAMH.

Dark poetry surfaces

A series of graphic and alarming poems have surfaced online and have been linked to Wettlaufer.

The National Post reports that the following poem, titled “Inevitable,” was penned by Wettlaufer and posted online under the pseudonym Betty Weston: “Heart beats then sprays/as this next victim pays/her deft dagger’s bill, Does it quench her craze? Sharp thirst recedes as she dances in blood – satiated for now no longer a flood.”

In the comment section, Wettlaufer allegedly wrote: "I felt it would make it more sinister to have the killer be a woman as it is unexpected. It also made me feel powerful."

It appears Wettlaufer also wrote about her journey to sobriety on Facebook.

A profile under the name Bethe Wettlaufer includes a Sept. 2015 post about overcoming addiction: “One year ago today I woke up not dead. 365 days clean and sober.”

Daughter had ‘eerie feeling’ about father’s death

More details are emerging about the eight elderly patients who died and the circumstances leading up to their deaths.

Police have identified the victims as James Silcox, 84, Maurice Granat, 84, Gladys Millard, 87, Helen Matheson, 95, Mary Zurawinski, 96, Helen Young, 90, Maureen Pickering, 79, Arpad Horvath, 75.

Seven of the victims lived at a Woodstock nursing home, Caressant Care, except for Horvath, who lived at Meadow Park Long Term Care in London.

The daughter of the youngest victim, Horvath, said that she’s harboured “an eerie feeling” for years that her father’s death wasn’t natural. Susan Horvath said she complained to nursing home administration that her father was being assaulted.

Then one day, Horvath suddenly slipped into a coma. He died shortly after.

“When I spoke with the police I already put two and two together and I figured out that he was in a coma because, in my words, somebody didn’t want him to talk,” Horvath told CTV Kitchener.

“And that was exactly how I felt, and so they basically reiterated what I suspect. And I know it sounds strange, because normally normal people wouldn’t suspect this. But I had this eerie feeling.”

Many of the victims were active members of their churches, such as Gladys Millard of Woodstock.

“I will certainly remember Gladys and the other victims as part of my prayer,” said Rev. Mark McLennan from Knox Presbyterian Church.

McLennan said he knew Millard quite well and that “her life was a sermon.”

“An example of Christian living that just about anybody could follow. And that’s the finest tribute anybody could have,” McLennan said.

The reverend said some parishioners have asked whether a community-wide memorial will be held. McLennan said nothing has been planned, but he thinks it would be a good idea.

CAMH response

Questions have been raised about existing rules around a doctor or medical professional speaking with police about private information disclosed by a patient.

Health-care providers are often restricted by patient confidentiality rules, but in some serious situations – such as cases possibly involving a suspicious death – they are legally required to contact police without a patient’s permission.

For instance, according to Ontario law, doctors must alert authorities if there are reasonable grounds to believe that a nursing home resident has been harmed or is at risk of harm because of "improper or incompetent treatment or care, unlawful conduct, abuse or neglect."

The shocking case, which has yet to be tested in court, is the first of its kind in Canadian history.

"There is no precedent for this in Canada,” said true crime author Michael Arntfield. “There is no documented health care serial killer in clinical forensic literature."

Arntfield pointed to the poem allegedly written by Wettlaufer and suggested it seems to fit a trend seen in high-profile American crimes.

"If you look at the recent spate of mass shooters, there was always some narrative transcript left behind for people to read," he said.

Wettlaufer is scheduled to appear in court by video on Nov. 2, and she is seeking representation from Toronto criminal defence lawyer Brad Burgess.

CTV News has learned that the Crown attorneys assigned to the case include Fraser Kelly and former Kitchener Crown attorney Andre Rajna.

With files from CTV Kitchener, The Canadian Press and CTV's Peter Akman